While half the households in the study were unaware their consumption was being monitored, the other half were informed of the monitoring - at least for some of the time.

Households in this group were sent weekly postcards for a month telling them their electricity use was being monitored. However the researchers actually collected data for two months after this.

Schwartz and colleagues found that the households that were told they were being monitored used 2.7 per cent less electricity than the control group, which were unaware of any monitoring.

This decrease in energy use, however, did not last longer than the month they thought they were being monitored. Once the postcards alerting them to monitoring stopped, the energy consumption climbed back to normal levels.

Energy awareness

Schwartz says the fact that energy consumption was reduced only while there were weekly reminders suggests energy awareness plays a key role in the success of energy efficiency programs.

"In general we don't think about energy in our life very often, so any reminders to think about this energy issue helps to save energy," he says.

Schwartz says the findings will also help researchers account for the role of energy awareness when they are studying energy efficiency programs.

Ethics of study

Ambrose says the US study was well designed because people were not always aware their energy consumption was being monitored, but he says this presents ethical problems.

"We couldn't really undertake a study like that in Australia because we need to get permission from people to collect their energy consumption data," he says.

Schwartz says the study was approved by the institutional review boards of the universities involved in the research and at no stage was electricity consumption linked to the identity of specific individuals within the households being monitored.